Urine marking in dogs is a well-known behavior in the sense that everyone is aware that it happens, but it is poorly known in the scientific sense because so few studies have examined it with a rigorous approach.

Countermarking behavior in dogs consists of either marking on (overmarking) or near (adjacent marking) previous scent marks. Part of what’s so great about this study is that it shows that what we think we know about behavior from observing it casually, even over years and years, may not be as spot on (so to speak) as we think.

As is so often the case, a controlled study of the relevant variables revealed that what is going on is significantly more complex than previously believed. Lisberg and Snowdon’s study is one of a few to examine canine urine marking and as such makes a big contribution to our understanding of this behavior. Here’s what their study found:

In an experiment with urine from groupmates and from unfamiliar dogs presented to dogs in a controlled way on sticks, they found that:

Intact males (but not neutered males) were more likely to overmark urine from intact females.

Males who overmarked had a higher tail base position (which the authors used as a measure of social status) than males who did not overmark.

Familiarity with a dog did not affect overmarking of its urine, but dogs adjacent-marked only urine samples from unfamiliar dogs.

Neither sex nor tail base position affected adjacent marking.

Being spayed or neutered had no relationship with the likelihood of countermarking.

In observations of countermarking at a dog park, they found that:

Males and females both countermarked and investigated urine.

Males and females with higher tail base positions did more urinating, countermarking, and investigating of urine than members of their same sex with lower tail base positions.

Lisberg and Snowdon conclude that although intact males may be overmarking intact female urine as a form of mate guarding as has long been suspected, that is only a piece of the story. Both sexes, whether intact or not, appear to countermark in a competitive manner. Additionally, this study suggests that overmarking and adjacent marking may have different functions.